ellerbeck



Oct. 18, 1960 G, c. ELLERBECK CALCULATOR CENTRALIZING MECHANISM 2 Sheets-Sheet 1 Filed April 29, 1957 Oct. 18, 1960 ca. c. ELLERBECK 2,956,744

CALCULATOR CENTRALIZING MECHANISM Filed April 29, 1957 2 Sheets-Sheet 2 "ll! Z 35 United States Patent CALCULATOR CENTRALIZING MECHANISM Grant C. Ellerbeck, San Leandro, Calif., assignor to Friden, Inc., a corporation of California Filed Apr. 29, 1957, Ser. No. 655,800

Claims. (Cl. 235-73) This invention relates to calculating machines and more specifically to a centralizing mechanism for the selection gears of a Thomas-type calculating machine.

A primary object of the present invention is to provide a centralizing mechanism adapted to positively position the selection gear of a Thomas-type calculating machine in the proper value position, especially in those machines in which the position of the selection gear is automatically changed from one value position to another during continuous cycles of machine operation, such as in my patents on machines for the extraction of square root, Nos. 2,736,493 and 2,736,494, issued February 28, 1956, or the back transfer machine described in the copending application of Malavazos, S.N. 736,091, filed May 19, 1958.

Another object of the present invention is to provide a locking device associated with the selection mechanism of a full keyboard calculating machine to prevent alteration thereof during particular portions of the machine cycle or to prevent bounce of the selection gear during machine operation.

It is a still further object of the present invention to provide a safety device in a calculating machine for positively preventing the accidental change of a selected value during the digitation phase of machine operation.

A still further object is to provide a locking cylinder for the selection gear of a Thomas-type calculating machine, whereby, after a key is depressed, further movement of the associated selection slide is prevented while calculation is taking place.

A still further object of the present invention is to provide an improved structural arrangement in a calculating machine whereby a value entered in the selection mechanism is positively locked therein during the digitation phase of a cycle of operation to prevent any change in the value position of that selection gear during that phase of operation.

These and further objects of the present invention will be readily understood from the following description taken in connection with the drawings in which:

Fig. l is a fragmentary cross-sectional view of a selection and actuating mechanism of a Thomas'type calculating machine, taken along a vertical longitudinal plane extending through a conventional calculating machine.

Fig. 2 is a plan view of a pair of adjacent orders of the selection mechanism, such as a view taken along the horizontal plane indicated by the line 2-2 of Fig. 1.

Fig. 3 represents a front view of the pair of adjacent orders shown in Fig. 2, such as taken along the transverse vertical plane indicated by the l-ine 3-3 of Figs. 1 and 2.

The present invention has particular value in connection with calculating machines in which the selection gears are positioned to different value positions between the digitation phases of sequential cycles of operation as, for example, in the machines for the extraction of square root described in my Patents Nos. 2,736,493 and 2,736,- 494, both issued on February 28, 1956, or in the back transfer machine of the copending application of Arthur Malavazos, S.N. 736,091, filed May 19, 1958. It will be 2,956,744 Patented Oct. 18, 1960 understood that it is conventional in machines of this type to perform the digitation and the subsequent tenstransfer as a wave beginning with the right-hand order, so that the digitation and tens-transfer phases of any particular cycle ends, in the left-hand order, shortly be fore the end of that machine cycle. In the square root machines particularly, the extraction begins on the lefthand side of the keyboard, so there is only a slight interval left in the cycle following digitation phase. It will also be recalled that in these machines the selection mechanism is operated by the power drive of the machine to progressively position the selection slides, and consequently the selection gears, to successive value positions during the tens-transfer phase of each cycle, so that progressive values are set in the selection mechanism in each cycle of machine operation. With machines operating at high speeds, such as is conventional in machines of this class, there is some tendency for the selection bars to bounce and hence there is a possibility of error if the digitation phase of the next cycle begins too soon after the change in the selection mechanism. It is obvious that unless the selection gear is substantially in its full value position at the start of the digitation phase, it may slip off the proper teeth of the actuator and hence throw an incorrect value. My mechanism is designed to positively centralize these slides and gears in the proper position. In a properly designed and fabricated machine the bounce is minute, but it can readily develop to a point where it may cause an occasional error in machines subjected to considerable wear, or in which the workmanship is not up to standard. However, I have found that even in such machines the bounce never amounts to half of a digital value spac ing, so that they will operate with the utmost accuracy when I centralize the selection gear to the closest value position, as will be described hereinafter. For purposes of illustration, my invention will be shown as embodied in a calculating machine of the type described in the patent to Friden, No. 2,229,889 of January 28, 1941, but will will be understood that it can be applied to any conventional calculating machine.

Numerical values may be selected for entry into the accumulator mechanism of the machine by depression of appropriate numeral value keys '10 of a conventional full keyboard. The keys are arranged in a plurality of orders, each order containing value keys from .1 to 9, inclusive, only one such key being shown in Fig. 1. The various keys 10' are arranged for vertical movement in a keyboard frame 11 mounted in the machine, as by means of key slots 12 embracing tie rods 13 which extend transversely across the keyboard frame. The keys are resiliently biased to a raised position by suitable springs, not shown herein. There is a latching slide 14 associated with each order of the keyboard keys, which slides are provided with a series of apertures 15, each of which embraces a key stem 10. The latching slides are normally urged toward the front of the machine (left in Fig. 1) by means of conventional springs, not shown. Each key, when depressed to its operative position, causes a notch 16 in the rear edge of the key stem to register with the latching slide 14, which is then forced forwardly by its spring to enter the notch and thereby lock the key stem in its operative position.

Preferably, as is shown in Fig. 1 and more fully described in the patents mentioned, there is a pair of similar value selecting, or V-notch, bars 20 associated with each order of the keyboard keys 10. These bars are mounted for longitudinal movement by any suitable means, such as a pair of parallel supporting arms 21, only one of which is shown. These bars are provided with a set of differentially set cam faces 22 which cooperate with pins 17 on the lower ends of the key stems 10, whereby the selection bars 20 are translated a differential amount depending upon the value key operated. It is conventional in these machines to have one bar serve the 1 to 5 keys of each order and the other bar to serve the 6 to 9 keys. The selection bars 20 extend rearwardly through a crossframe member 23 of the machine, each terminating, at its rear end, in a right angular yoke 24 that engages a grooved collar 25 on a ten-toothed selection gear 26. The selection gears are slidably and non-rotatably mounted on a longitudinally extending square shaft 27 journalled in the crossframe members 23, 28 and 29. Hence, the depression of a value key results in a differential translation of the associated selection bar 20, which, in turn, differentially positions the related selecting gear 26 axially along the square shaft 27.

The differential movement of the selecting gears 26 on the square shaft 27 positions the gears in the path of travel of a series of stepped teeth provided on the conventional Thomas-type, or stepped drum, actuators 35. These drums are mounted on a series of longitudinally extending actuator shafts 36, all of which are driven in unison by means of miter gearing connecting them with a main drive shaft 37. The shaft 37 is cyclically and unidirectionally operated by means of a clutch controlled drive means described in the patents hereinbefore men tioned, and hence all of the actuators are cycled in unison with the rotation of the drive shaft. It follows that the actuator drums 35 are operative to rotate the selection gears 26 and the square shafts 27 on which the latter are mounted, differential amounts depending upon the differential axial position of the gears on the respective square shafts. It can be mentioned that it is conventional in the machines mentioned to mount two drums on each actuator shaft, one drum operating the selection gears on the order to the right of the actuator shaft and the other drum operating the selection gears on the square shaft to the left thereof, as shown in Fig. 3.

While the accumulator 70 is in one sense not a part of the present invention, it can be briefly mentioned that conventionally it comprises a series of dials, as shown in Fig. l, mounted upon ordinally arranged dial shafts 71. An accumulator, or dial, gear 72 is mounted on the lower end of each dial shaft 71 and is driven in either an additive or a subtractive direction by means of a gear spool 73 which is slidably mounted on the rear of each square shaft 27. The gear 73 may be positioned in either an intermediate inoperative position shown in this figure, or rearwardly or forwardly to its additive or subtractive positions by means of a gate 74, as is conventional in the art. Conventional means for effecting interordinal tens-transfers in such a register is shown in Fig. 1, but is not described as it forms no part of the present invention. Reference is made to the patents hereinbefore mentioned for a complete disclosure of the register and transfer portion of these mechanisms, as well as the drive and controls therefor. The present invention relates primarilyto the centralizing of the selection gears 26 in a proper differential position to be operated by one of the series of mutilated gears comprising the actuator drums 35, and to lock the selection gears 26 in the proper position, so that only the portions of the machine relating to this mechanism and its operation need be described.

The centralizing mechanism of the present invention comprises broadly a locking cylinder 50 or 50-41 slidably mounted on the square shafts 27 and operatively connected to the related selection gear 26 and an associated centralizing and locking disk 60' rigidly mounted on an actuator shaft 36. In those orders in which the selection gears are mounted toward the front of the machine (shown on the left in Fig. 2), the centralizing and looking drum 50 may comprise the forwardly extending collar on the associated gear 26 (as is shown on the left in this figure). In those orders in which the selection gears are mounted toward the rear of the machine, as is shown on the right in Fig. 2, the drum can be entirely separate from the associated selection gear, as is shown at 50-a. In this event the drum 50-a is provided with a peripheral notch 51 that is embraced by a yoke 52 riveted to, or otherwise rigidly mounted on, the associated selection slide 20. In order to conserve space, which is at a premium in machines of this kind, it is desirable to use only one centralizing plate, or disk, 60 on each drive shaft 36, and it is therefore preferred to place the ordinal centralizing cylinders 50 and 50-a in transverse alignment across the machine. For purposes of my invention it is immaterial whether this locking cylinder is integral with the gear, as is shown on the left in Fig. 2; or is separated therefrom, as shown on the right, but is locked in spacial relationship with the gear through the media of the yokes 24'and 52 which are held in rigid spaced relationship by means of the associated selection slide 20. In this connection it can be mentioned that I have found that errors most often occur in connection with the values 1 to 5, especially if this invention is used in connection with the back transfer mechanism of the Malavazos application, so that in most instances it will be satisfactory to use the locking drums 50 in connection with the selection gears 26 which serve the 1 to 5 keys and to omit such drums in connection with the other selection gear in each order.

Each locking drum 50 or 5tl-a is provided with a series of V-notches 53. Cooperating with the V-notches is a centralizing plate, or disk, 60 rigidly mounted on the actuator shaft 36 and preferably locked against the forward actuator drum 35, as by means of lock nut 62. Preferably this disk 60 has a knife edge 61, as shown particularly in Figs. 1 and 2, and extends only through an angle corresponding to the digitation phase of a machine cycle. The forward, or leading, edge of the plate 60 should engage one of the associated V-notches 53 shortly before the engagement of the associated actuator teeth (of the 5 gear in the embodiment shown) with the related selection gear. Obviously, the rotation of the disk 60, through its engagement with one of the V-notches 63, will positively position the locking cylinder 50, and with its the selection gear 26 in the proper digital value position before engagement of the leading tooth on the actuator drum with its selection gear. -It is also obvious that by using V-notches in the locking cylinder and a knife edge on the earn, it is impossible for the rims of the V-notches and the edge of the plate to meet in a manner to cause locking of the machine, for the knife edge will enter one or the other of the V-notches, and will positively and accurately position the related related gear in the proper position. It follows that during a predetermined portion of the digitation phase of a cycle of machine operation (extending through an angle beginning ahead of the leading 5 tooth on the actuator drums and extending through an angle terminating at approximately the last tooth position of the last effective drum, as shown particularly in Fig. 3), the selection gear is locked against lateral displacement during the digitation phase of each cycle. It also follows that even though the selection gear is in its bounce at the start of a cycle of operation, the disk 60 will drive it to its full value position before digitation starts. While the locking arrangement herein shown and described is associated only with the left-hand selection slides 20 in each order, which serve the 1 to 5 keys of that order of the keyboard, it will be apparent that the locking arrangement can be used in connection with the 6 to 9 keys and their selection gear by merely lengthening the space between the crossbar members 23 and 28.

When any selection bar 20 is moved to roughly position the selection gear 26 in its proper position in connection with its actuator 35- a specific V-groove 53 will be in substantial vertical alignment with the segmental plate, or blade, 60, whereby rotation of the actuator shaft 36, upon operation of the machine, will cam the related locking drum 5t) forwardly or rearwardly, as the case may be, to accurately position the selection gear 26 in the proper position with respect to its actuator. Since the disk 6% is made rigid with the actuator shaft 36, as by virtue of locking nut 62, and the shaft 36 has no longitudinal movement in its bearing, it becomes physically impossible to move the selection gear 26 out of its proper position as by accidental depression of another key in the l to 5 series. This is a problem which is of no particular importance when positioning of the selection gears comes from hand operation of the keys 10, for the gear is not subject to bounce in that situation, and if it were it would have time to become centralized before the machine would be operated. It does become a problem of considerable importance when the selection slides 20 are adjusted to successive value positions by a power-operated mechanism between sucessive cycles of continuous operation, as in the square root patents previously mentioned. These machines operate at high speed, and the selection bars 2%) must be moved from one vaue position to the next while the machine is turning through an angle of only a few degreessometimes having about 0.01 second to change the value position of the selection bar and gear, and centralize them in proper position, before digitation begins in the next cycle. in such circumstances there is a tendency for the selection bars 29 to bounce, or rebound, and if the next cycle of operation causes the operative tooth on the actuator drum 35 to engage the selection gear 26 as that gear is moving in one direction or another along shaft 27, an error may be caused. However, due to the fact that the locking blade 60 engages its associated V-notch 53 prior to the engagement of the teeth of the actuator drum with the selection gear associated with the locking cylinder, the disk 62 will positively cam, or push, the gear to the proper position and lock it in that position throughout the remainder of the digitation phase. Thus an error becomes impossible.

I claim:

1. In a calculating machine having a plurality of parallel drive shafts, a pair of Thomas-type differentially stepped gear actuators having nine teeth corresponding to the values of 1 through 9 mounted on each of said drive shafts and angularly positioned with respect to each other, an accumulator, a pair of selection shafts parallel to each of said actuator shafts, drive coupling means between said selection shafts and accumulator for driving the latter, axially shiftable pinions on said selection shafts for alignment with a differential portion of a respective actuator, and selection members adapted to move said pinions into alignment with a selected differential portion of the respective actuators, a locking means effective to prevent axial movement of said sh-iftable pinions during operative engagement with said actuator which comprises a cylinder having a plurality of annular grooves slidably mounted on said selection shafts and rigidly connected to a pinion on the respective selection shafts so to be moved longitudinally along said shaft simultaneously with the shifting movement of the pinion thereon, a segmental disk with a blade-like edge rigidly attached toeach actuator shaft for rotation therewith and extending through an angle corresponding to the 1 to 5 teeth on the pair of associated actuators, said disks being in engaging alignment with a groove in the related cylinders when the connected pinions are in alignment with a selected differential portions of said actuators, whereby said shiftable pinions are limited in axial movement once said disks and cylinders are engaged.

2. In a calculating machine having a driving shaft, a stepped actuator on said shaft, a driven shaft, and a selection gear differentially positionable axially on said driven shaft and operable differentially by said actuator for determining the amount of rotary movement to be imparted to said driven shaft by said actuator, a locking means effective to prevent change in axial positions of said selection gear during rotation of said driving shaft which comprises a fragmentary blade on said actuator shaft and a locking drum having a plurality of annular grooves rigidly connected to said selection gear, the grooves of which are adapted to be engaged by said blade in various differential positions of said gear.

'3. In a calculating machine having a power-operated stepped drum actuator, an accumulator, a shaft supporting said actuator, a second shaft parallel to said actuator shaft, drive coupling means between said second shaft and said accumulator for driving the latter, a pinion shiftable axially on said second shaft for alignment with the various steps on said actuator, selection means to move said pinion into alignment with a selected step of said stepped drum actuator, a shiftable locking member on said second shaft rigidly connected to said pinion for axial movement therewith, a second locking member rigid with said actuator, one of said locking members comprising a drum having a plurality of annular grooves and the other comprising a sector with a blade-like edge adapted to engage a groove of said drum during rotation of said actuator shaft, said shiftable locking member being further adapted for alignment with said actuator locking member when said pinion is aligned with a selected step of said actuator, whereby said second locking member is aligned to engage said shiftable locking member and prevent further axial movement of said shiftable pinion while the driving movement between said actuator and said pinion is taking place.

4. In a calculating machine having Thomas-type differentially stepped gear actuators, an accomulator, a first series of shafts supporting said actuators, a second series of shafts parallel to said actuator shafts, drive coupling means between said second shafts and said accumulator for driving the latter, axially shiftable pinions on said second shafts for alignment with differential portions of said actuators, and selection members adapted to axially move said shiftable pinions into alignment with selected differential portions of said actuators, cylinders having a plurality of annular grooves sl-idably mounted on said second shafts and rigidly connected to said shiftable pinions to be moved simultaneously with the pinion thereon by said selection members, segmental disks rigidly attached to said actuator shafts for rotation therewith, said disks having blade-like edges and being in engaging alignment with a groove in the related cylinders when the pinions rigidly connected to said cylinders are in alignment with said selected differential portions of said actuators, whereby said shiftable pinions are locked against axial movement once said disks and cylinders are engaged.

5. In a calculating machine having a rotary steppeddrum actuator, a shaft adapted to be driven by said actuator, and an axially shiftable selection gear differentially positionable on said shaft for determining the amount of rotary movement to be imparted to said shaft by said ac tuator, the combination which comprises a locking member rigidly connected to said actuator and a mating locking member rigidly connected to said selection gear, one of said locking members having a blade extending through an arc approximating the arc of engagement of the actuator and the selection gear and the other of the locking members having a plurality of mating grooves each adapted to mate with said blade in a different differential position of said selection gear, whereby said locking members are adapted to mate in the various operative posi tions of the selection gear.

References Cited in the file of this patent UNITED STATES FATENTS 1,370,493 Blaustein Mar. 1, 1921 1,392,847 Odhner Oct. 4, 1921 2,229,890 Friden Jan. 28, 1941 FOREIGN PATENTS 832,506 Germany Feb. 25, 1952 

